DESCRIPTION: Given the formation and subsequent sloughing off of microbial biofilms from the inner surfaces of plastic tubing, Dental unit water is heavily contaminated with microorganisms. These microorganisms pose a potentially significant threat to Dental-care workers and patients, particularly those who are medically compromised or immunocompromised. The long-range goal of this project is to use N-halamine-based rechargeable antimicrobial tubing to control the formation of Dental unit waterline biofilms. The Specific Aims of the proposed research are to: 1) covalently bind N-halamine structures into plastic tubing, using simple and practical grafting methods; 2) characterize the antimicrobial activity, rechargeability, and mechanical properties of the new tubes; 3) evaluate the biofilm-controlling function and the safety of the new tubes in model Dental water delivery systems; and 4) provide preliminary data on the cost of the new approach. [unreadable] [unreadable] To achieve these goals, in the proposed research, polymerizable N-halamine precursors will be covalently bound onto plastic tubes using a "reactive-extrusion" approach. After extrusion, the new tubes will be treated with chlorine bleach to transform the covalently bound N-halamine precursors into N-halamines. [unreadable] [unreadable] The antimicrobial activities, stabilities, and rechargeabilities of the new N-halamine-containing [unreadable] tubes will be fully characterized. Selected tube samples will be challenged in model Dental water delivery systems with mixed species of water-borne bacteria to test the biofilm-controlling efficiency of the tubes. The cost-effectiveness of the new approach will be further evaluated. [unreadable] [unreadable] If successful, the rechargeable antimicrobial tubing technology will provide an innovative solution to the [unreadable] biofilm problem in Dental unit water delivery systems. Furthermore, the antimicrobial plastic tube materials to be developed in this study may also find applications in other clinically important surfaces. All these will make significant contributions to a better and safer healthcare environment. [unreadable] [unreadable]